


five days

by parsnipit



Category: Undertale (Video Game)
Genre: (last two are primarily medical), Alcohol, Blood and Injury, Drugs, Emotional Hurt/Comfort, Established Relationship, Fluff and Angst, Hurt/Comfort, M/M, Nerds in Love, Pre-Canon, Soul Bond, Soulmates, Wartime, and a smidgen of humor there at the end
Language: English
Status: Completed
Published: 2019-11-17
Updated: 2019-11-17
Packaged: 2021-02-07 15:30:57
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,048
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/21460333
Author URL: https://archiveofourown.org/users/parsnipit/pseuds/parsnipit
Summary: Five days. That’s how long Gaster has been gone, lost, missing in action—five days. That’s how long Asgore has been amassing troops to find him. That’s how long Toriel has been pleading with the humans for their Royal Scientist’s life, should he be found behind their lines. That’s how long Grillby has been running himself ragged, burning his way through battalions and barricades and bunkers.The sixth day, Grillby finds him.
Relationships: W. D. Gaster/Grillby
Comments: 14
Kudos: 105





	five days

Five days. That’s how long Gaster has been gone, lost, missing in action—five days. That’s how long Asgore has been amassing troops to find him. That’s how long Toriel has been pleading with the humans for their Royal Scientist’s life, should he be found behind their lines. That’s how long Grillby has been running himself ragged, burning his way through battalions and barricades and bunkers. 

The sixth day, Grillby finds him. 

That morning, Grillby prowls the outskirts of a monster village, long destroyed by the human’s initial march towards Ebott. The buildings all lie quiet and abandoned now, coated in a thin layer of dust and ash. Grillby makes his way towards the husk of a shop, and he stumbles over a fractured rafter. He pinwheels his arms to catch his balance, then stands, sparking with irritation, once he has. It’s this momentary pause that gives his eyes time to scan his surroundings—this pause that leads them to land on a blur of red and white. 

His soul staggers, and he with it.

He takes a trembling step forward. His hands shake. A skeleton—there’s no doubt about it. What’s worse, it’s clearly an  _ injured  _ skeleton. Blood smears the ground around it. Not much, not as much as would be produced by flesh, but enough to let Grillby that there’s a marrow-wound involved. That’s going to be one very unhappy skeleton—and where there’s a very unhappy skeleton, there are usually very unhappy blasters.

Grillby treads carefully.

“...Wing?” he tries. His voice cracks. (He doesn’t know what he’ll do if Gaster is dead. Even considering it sends a bolt of panic through his chest. Gaster isn’t dead. He  _ isn’t dead.)  _ “Wingdings?”

The skeleton stirs, and Grillby just about melts into a puddle of magma with relief. The skeleton’s skull turns towards him, and he sees the glint of a dull eyelight, the pit of a familiar crack running from cranium to eyesocket. As soon as he sees that, he’s moving. He couldn’t stop himself from stumbling forward if he had tried. That’s Gaster. That’s  _ Gaster,  _ that’s his best friend, his partner, his  _ soulmate.  _ He’s alive—oh, thank the stars, he’s  _ alive. _

Now Grillby has to keep him that way.

Unfortunately, stepping forward in such a hurry seems to cross whatever invisible barrier Gaster had drawn in his mind, and Gaster lets him know about that very clearly. A blaster cracks into life in front of him with a furious shriek, magic already humming in its jaws. Grillby doesn’t hesitate. He lurches forward, pressing his palms to the blaster’s nasals and pushing down. The blaster’s teeth clack shut. At the same time, he feels its magic curl around his own, feels it scent his palms. Its eyelights waver as soon as it recognizes him, and it warbles in despair. 

“It’s alright,” he promises, leaning his head against its muzzle and stroking soothingly beneath its chin. “It’s alright, shhh, hush now. I’m here. You don’t need to be afraid. Do you hear that, Wing?” He raises his voice slightly, looking past the blaster. “It’s only me. You don’t have to fight anymore.”

He edges past the blaster, giving it one last consoling pat before lowering himself to his knees beside Gaster. “What’s wrong?” he asks, raking his eyes over the skeleton. There are thin gouges and dirt just about everywhere, but he doesn’t see any wound that should have stopped Gaster from getting home. “Where are you hurt?”

Gaster’s eyes meet his, and for a long, terrifying moment, there is no recognition in his gaze—only black, hideous fear. Then he blinks. The blaster behind them dissolves. “...Grillby?”

“Yes.” Grillby leans down, pressing his forehead gently to Gaster’s. He lets out a wobbly laugh. “Yes, it’s me. Stars, I’ve been looking for you  _ everywhere.  _ Tell me what’s hurt.” He reaches out, his hands flickering frantically over Gaster, unwilling to touch him anywhere lest he cause pain. 

“What are you doing here?” Gaster asks, squinting blearily at him. “How did you…?”

“Shh, I’ll tell you later.” He reaches out, setting a hand tentatively on Gaster’s shoulder. He’s warmer than usual—warm enough that even Grillby can feel it. Shit, he’s got to be sick. Grillby tugs lightly, trying to coax the skeleton onto his back, but Gaster winces and curls up more tightly. “Come on, Wings, let me see. I have to know where you’re hurt so I can help.”

“Ow,” Gaster says plantitively; there’s a miserable, feverish gleam in his eyes.

“I know,” Grillby soothes, running a hand gently over Gaster’s spine. “I know it hurts. I can try to make it stop hurting, but I’ve got to be able to see it. Be brave for me, alright?”

When he pulls at Gaster’s shoulder again, Gaster reluctantly allows himself to be rolled onto his back. There are several thin fractures through his ribs, and a nasty-looking split in his sternum, but the worse wound is, by far, the vicious crack down his humerus and into his ulna. Blood and marrow crust around the edges, and Gaster holds his arm protectively to his chest. He clicks his teeth nervously as Grillby leans in to get a closer look, and Grillby hushes him softly.

“Shh, it’s alright. I’m not going to touch it without telling you. It’s infected, isn’t it?” He rocks back on his heels, scrubbing his face. He needs to get Gaster to a healer—and quickly. “Okay. Okay, I’m going to get you home, and Queen Toriel can take a look at you. She’s been worried sick. Everyone has been.”

Gaster looks wearily at him. Grillby...isn’t sure how much of this he’s actually comprehending, the poor thing. He reaches out, smoothing a hand over Gaster’s skull. The skeleton leans into him with a cracked purr, eyes drifting shut. Grillby can’t resist offering him that little bit of comfort, so he pauses for a moment to simply pet Gaster’s skull. It’s been too long since he felt a friendly touch—any day that passes without a friendly touch for Gaster is too long, in Grillby’s opinion. (Especially since he’s a skeleton who thrives so very much on attention and affection. To neglect him so is akin to purchasing a thoroughbred and harnessing it to a plow; a waste and a foolish cruelty.)

“Come, now,” he murmurs, cupping Gaster’s face and smoothing a thumb across his cheek. “We need to leave. We’re not far from the lines, but it’s going to be a bit of a trip. Can you walk?”

Gaster blinks hazily at him before closing his eyes, nuzzling into Grillby’s hands. 

“...right.” Grillby exhales softly. “Okay, scratch that. I’ll carry you. Do you think you can handle that? I’ll be as gentle as I can, but—”

Something cracks behind them. Gaster’s eyes snap open, and before Grillby can react, the skeleton staggers to his feet, an inhuman snarl echoing beneath his ribs. A blaster head sparks to life behind him, its eyes blazing. Despite his exhaustion (stars, he’s swaying in place—he can hardly stand), Gaster’s eyelights gleam purple as he summons his power. Blue magic wreathes around his hands. 

“Hey, hey hey—” Grillby stands, resting a hand on Gaster’s chest to keep him from moving (or, you know, toppling) forward. “Be careful.” While he appreciates Gaster’s survival instincts—they are, no doubt, why his soulmate is still alive after so long in human territory—he also knows Gaster is in no shape for a fight.

Grillby glances behind himself and sees who had startled Gaster so: a troop of humans some distance away, marching towards the town. The clatter of their horses’ hooves on the cobblestone grows louder as they near, and Grillby’s soul twists. He has a decision to make. They can attempt to fight their way through the humans, but the chances of them winning against such a large company...well. It’s not worth it. Grillby may be hot-blooded, but he’s no  _ fool. _ Their only other option is to hide and hope the humans pass through without seeing them. 

It’s an easy decision.

Grillby clamps one hand over Gaster’s mouth, then scoops him up. Gaster goes rigid in his arms, hissing out a pained breath against his palm. He opens his mouth to speak, and Grillby pushes down with his hand. Gaster growls but clicks his teeth together again. Grillby eases his way across the remains of the building, ducking down behind a pile of shattered brick. He sets Gaster down in front of him, keeping one hand carefully over his mouth.

“The blaster,” he whispers. “Get rid of the blaster. We have to hide so they’ll pass us over.”

(He prays they’ll pass over.)

Gaster hesitates, his eyelights flickering towards his blaster. Sparks crackle between its teeth, and it tilts its head towards him, its own eyelights mere slivers of white in its sockets. For a moment, Grillby fears Gaster won’t listen, and he fears what he’ll have to do a result. He’ll knock Gaster out, if he has to, but he knows (from unfortunate experience) that it would make him sick to do so, and he’d be wallowing in self-loathing for months. Fortunately, Gaster isn’t in quite that cantankerous of a mood. He sighs, and the blaster fizzles out of existence. 

“Well done. Thank you,” Grillby murmurs, leaning their heads together. He drops his rucksack to the ground beside them, then pulls his cloak up and over their heads to hide the light he gives off. The air between them rapidly grows stuffy and overheated, but Gaster doesn’t complain.

“Where are we?” Gaster asks, his voice muffled by Grillby’s palm. “Spark? Where—”

Grillby hushes him softly as the humans grow closer. He keeps his hand gently over Gaster’s mouth, and Gaster squirms unhappily but allows it, falling mercifully silent. The humans, fortunately enough, stick to the road. Within minutes, they’ve passed by. Grillby waits a few moments longer, just to be sure there isn’t another troop following them. After that, he uncovers Gaster’s mouth. Gaster clacks his teeth in distaste.

“You smell like smoke,” he says accusingly. 

“Stars, I can’t imagine why.”

“Have you been smoking?”

“No, dear.”

“I don’t like it when you smoke.”

“It doesn’t harm me at all. We’ve been over this.”

“I don’t like it.”

“Then I’ll stop right away.” Grillby doesn’t remind Gaster that he hasn’t smoked for years now. He hasn’t smoked since the first time Gaster told him to stop <strike>had told him it reminded him of things better forgotten.</strike> Instead, he ruffles his palm gently over Gaster’s skull, then moves to crouch in front of him. “May I see your arm?”

Gaster looks uncertainly at him, hugging his arm securely to his chest. “It hurts.”

“I know it does, sweetheart. I want to make it stop hurting, but I’ve got to be able to see it.” Grillby leans forward, kissing Gaster’s forehead. “You can tell me to stop any time you need me to and I will.”

“Promise.”

“I promise.”

Gaster gingerly relaxes his grip on his own arm, and Grillby reaches forward to cradle it—one hand under the elbow and one under the wrist. He extends it for Gaster, wincing as he sees the full extent of the damage. Filth and pus cake the edges of the crack, and the magic sealing it together glows sour and gray. Grillby can’t help but wonder what the hell he did to infect it so quickly, but he shoves the thought away. A question for another time, when they’re safe and sound at camp and Grillby can have an absolute breakdown because he was afraid, he was  _ so afraid— _

Another time.

“Alright,” Grillby says, rummaging through his rucksack with his free hand. “I’m going to clean it and bandage it to keep it still for you. Would that be alright?”

Gaster hesitates, then nods, watching Grillby’s every move with a wary eye.

Grillby pulls a tattered washcloth and his canteen from his bag. He dampens the far edge of the washcloth, careful not to get the water on his hands, and then begins to wipe the grime away from the edges of Gaster’s wound. Gaster winces but tolerates the procedure as best he can—that is, until Grillby tries to clean the filth from the  _ inside  _ of the wound. As soon as the washcloth dips into his bone, Gaster rattles his bones in agitation, instinctively trying to pull his arm back to himself. 

“Hey easy, easy, you’re okay,” Grillby soothes, keeping a firm grip on Gaster’s arm—best he doesn’t jar it too much. “Does that hurt too much?”

Gaster nods miserably. “Can you stop now please?”

Grillby...hates to leave Gaster’s wound so dirty, but he also can’t bear to hurt his soulmate any longer. With any luck, they’ll be home by tomorrow morning, and someone more professional than he can knock Gaster out and scrub the wound before sealing it. Moreover, he promised Gaster he would stop when he was asked to—to go back on that now would be to shatter Gaster’s trust in him, and the idea of that revolts him.

“Yes, I’ll stop,” he agrees, setting the washcloth aside. “I’m just going to wrap it now. I’ll be done quickly.”

He binds Gaster’s arm snugly in a thick white bandage to keep the bones from jostling. Gaster’s breath hitches in pain as the edges of his bones scrape together and realign, but once they’re in place, he settles quickly. (He’s too exhausted to do anything else.) Grillby binds his fractured ribs, too, then slings his rucksack back over his shoulders. He scoops Gaster up, cradling against him chest.

“Are we going home?” Gaster asks softly, leaning his head against Grillby’s chest. “I don’t feel good.”

“I know you don’t, little one. We’re going home right now. You can rest—I’ll wake you when we get there.”

“Okay.” He rubs his cheek against Grillby’s chest, closing his eyes. “Spark?”

“Yes?”

“I love you.”

Grillby’s soul warms, and he nuzzles the top of Gaster’s head, crackling his affection in his native language before murmuring, in Common, “I love you too. Never doubt it.”

With that, Grillby begins the march home. Gaster stays in his arms, drifting between a hazy sort of consciousness and flickering fever dreams. Several times, Grillby has to jostle him awake before he lashes out in his sleep—his magic froths with terror until his eyes land on Grillby, and then (oh, stars) that same vicious magic practically melts into him.

“Grillby,” Gaster says, his voice raw and wrought with the same awe each time—as though it’s the first time he’s seen Grillby in days and days. 

“Wing.” Grillby squeezes him gently each time. “It’s okay. You were just having a bad dream.”

“Oh.” Gaster rubs his eyes. “Where are we?”

“Almost home, my dear. Almost home.”

And Gaster will flash him that familiar, silly smile and say, “I’m always home with you, spark.”

Even in the middle of a war, with the weight of his injured soulmate in his arms and exhaustion burning along the backs of his shoulders, he finds that he can smile right back. 

They reach Ebott shortly after dawn the next day. Gaster flips the fuck out as soon as they do. This, of course, could be because the second Grillby sets foot in camp, they’re swarmed by soldiers and medics who all want to tear Gaster away from him and race him to the field hospital. Gaster is having absolutely none of that—he snarls as soon as the first person lays a hand on him, immediately beginning to struggle. A few fragmented, weak blasters attempt to spark to life.

“Enough,” Grillby snaps at the medics, stumbling backwards and desperately readjusting his grip to keep Gaster in it.  _ “Enough,  _ all of you. Back up.”

They back up, although the clamor around them doesn’t reduce at all. 

“Wingdings.” Grillby presses his mouth to the side of Gaster’s skull, squeezing him tightly. “Wings, shhh, stop. It’s alright. No one is taking you. I won’t let them—you know I won’t let them.”

Gaster hisses, low and rattling. His eyes skitter frantically over the crowd until Grillby cups a palm over them, effectively blinding him. He stops trying to squirm his way out of Grillby’s arms, after that, although his breathing doesn’t slow at all. He brings one hand up, curling his fingers around Grillby’s wrist—but he doesn’t try to pry Grillby’s hand off, so Grillby leaves it firmly in place.

“It’s alright,” he repeats. “We’re back at the camp. The medics need to take a look at you to make you feel better.”

“No,” Gaster says.

“They won’t hurt you. If they have to do anything, they’ll put you to sleep first. Come on, we’ve been through this before.”

Gaster pauses, as though he’s thinking about it. Then: “No.”

Grillby momentarily entertains the idea of putting his own head through a wall. Stubborn, stubborn,  _ stubborn.  _ Why is his soulmate such a  _ stubborn creature?  _

“Okay,” Grillby concedes, and Gaster relaxes minutely. “You don’t have to let anyone do anything if you don’t want them to, but I’m still taking you to the tent, in case anything gets worse. That’s only logical.”

Even Gaster can’t argue that one, thank the stars. Grillby weaves his way through the crowd and into the field hospital, followed closely by a troop of medics. The medics quietly clear a cot for Gaster, and Grillby sets him down and removes his hand from Gaster’s eyes. Gaster blinks at him, then scowls. 

“What?” Grillby asks, folding his arms across his chest. “Come on, you can’t be mad at me. I got you home.”

Gaster’s face softens, and his shoulders slump. “...thanks.”

“You’re welcome.” Grillby reaches out, cupping Gaster’s face again. Gaster turns into his hand, eyes scanning the tent anxiously. Grillby feels his jaw click as he grinds his teeth, and he taps the edge of Gaster’s mandible gently. “What’s wrong? You know nobody here will hurt you.”

“I know. I just—I don’t know.” He groans, hugging his arm to his chest and pulling his knees up. “I feel like shit. Are we—we’re back at camp. At Ebott?”

“Mm-hm. Safe and sound at Ebott. The humans are miles away.”

“I don’t remember what happened. I feel fuzzy.” 

“You’re sick.” Grillby rubs a thumb along his cheek. “You’ve been sick for a while. The medics need to clean your arm and get you some antibiotics. I’m not going to tell you that won’t hurt, because it will, but they’ll knock you out first. C’mon, they’ve got laudanum, and enough alcohol to kill an elephant. That’s more than enough to put you out, little thing that you are.”

“Kill an elephant?”

“I don’t know, it’s a figure of speech? You didn’t have to latch onto that part.”

“It was the funny part.” A smile flickers across Gaster’s face.

“I’m glad you thought so. So will you let them take a look at you? The sooner you do, the sooner you’ll start feeling better.”

Gaster squirms uncomfortably. “What if something bad happens while I’m asleep?”

“I’ll stay with you the whole time. I’d never let anything bad happen to you, would I?”

Gaster shakes his head. “The whole time, you’ll be there?”

“The whole time.” 

“Okay,” Gaster says, reaching for Grillby’s hand. He squeezes it gently, pressing his teeth to Grillby’s knuckles. He nips gently—a skeleton’s lovebite. “Pour me a shot?”

Grillby pours him several shots, each laced heavily with laudanum. Gaster, lightweight that he is, is out within minutes. Only then does Grillby allow the medics to approach, and he keeps a close eye on them as they clean and bind Gaster’s wounds. As soon as Gaster begins to stir, he drives them off and finishes the bandaging himself. Then he curls up around his soulmate, flickering his flames as mildly as he can to convey his own calmness as Gaster wakes.

It takes several days for the fever to wane, and Grillby is more or less glued to Gaster’s side the entire time. Gaster doesn’t mind at all, greedy thing. He latches onto Grillby whenever he can, and the two of them spend their days reading and talking and joking. It’s a pleasant break from the war, although Grillby knows they can’t avoid it forever. Toriel and Asgore both come to visit, and each squishes Gaster into a hug that has him laughing and burrowing into them. 

The night before Gaster’s official discharge from the field hospital, he curls up in Grillby’s lap, pushing his way under Grillby’s novel to do so. “Yes, dear?” Grillby asks, setting the book on Gaster’s shoulder. 

“You came alone,” Gaster says.

“What?”

“When you came for me, you came alone. Why didn’t you bring anyone else? Your troop? Surely they would have been willing to come with you. They’d follow you to hell and back— _ have  _ followed you to hell and back.”

“I didn’t ask them to come.”

“I figured as much. Why not?”

Grillby shrugs.

“Grillby.” Gaster squirms up in front of the book, frowning at him.

“I was at a good part,” Grillby complains rather half-heartedly before setting the novel aside. He...doesn’t particularly want to talk about this. He knows what Gaster’s response will be. He’s only lucky he managed to put it off this long. 

“Why’d you come alone?”

Grillby sighs, leaning his head against Gaster’s shoulder. Gaster’s hand comes up to cradle the back of his head, fingers smoothing through his flames. “I panicked. When I heard you were gone, I just—I didn’t wait around. Mobilizing the search parties was taking too long. I had to get to you.”

“Oh, spark.” Gaster sighs—exasperated fondness. “What am I going to do with you?”

“Love me?”

“Always.”

“Kiss me?”

“Hmm—maybe.” He pushes Grillby’s chest, and Grillby leans back again. “But you shouldn’t do that again. I know it’s scary, and maybe I’m being a giant hypocrite right now, but—I don’t want you to get hurt because of me.”

“I know.” Grillby takes his hands, folding them gently between his own. “I’m sorry. I don’t know that I’m ever going to be able to sit back and wait when you’re in danger, but—I’m sorry it scares you.”

A sad smile flashes across Gaster’s face. “...ah, that’s alright. I guess that’s the life we have to lead, as long as we’re in this damnable war. I tell you what, people who think there’s glory in war piss me the fuck off. There’s nothing glorious about being separated from you. Or, you know. People dying I guess.”

Grillby snorts. “You guess, huh?”

“Yeah.” Gaster drapes his good arm over Grillby’s shoulder, leaning forward to kiss the bridge of his nose. “But, hey—thanks for coming for me, Grillby. Really. Even if you scared me, doing it all alone like that.”

“You’re more than welcome.” He grins, nuzzling their noses together. “I’ll bring the whole army for you, next time.”

“Let’s just not plan on a next time, ‘kay?” Gaster pushes forward, presses his teeth to the jagged sliver of Grillby’s mouth. For a moment, his magic dances along Grillby’s, warm and inviting and  _ happy.  _ It’s enough to make Grillby spark with elation, and several of his flames flicker between Gaster’s teeth. Gaster pulls back, laughing. “Stoooop, that  _ tickles.” _

“Oh, does it?” Grillby grins, leaning forward and trailing his fingers gently along Gaster’s uninjured ribs. “Did I get your funny bone?”

_ “Grillby!”  _ Gaster squeals, pushing his face. Grillby topples backwards rather dramatically onto the cot, laughing. Gaster kicks him gently in the side, his eyes shining. “Stars, I love you, you big dummy.”

“Dummy?” Grillby mimes offense, clutching a hand over his soul. “Why, I never—”

Gaster flops (gingerly) across him, peppering his face with tiny lovebites. “I  _ jest.  _ You’re smarter than people give you credit for, you know that?”

“Mm, I’ve got somebody who reminds me pretty regularly.” Grillby hugs Gaster, burying his face against the skeleton’s neck. “And hey, guess what?”

“What?” Gaster asks, a knowing lilt to his voice.

“I love you too.”

“Heh. Thanks.” He feels Gaster’s soul spark with delight and he knows that, even if only for tonight, everything is perfectly wonderful.

**Author's Note:**

> thanks for reading!! i hope you all enjoyed this lil oneshot! if anyone wants to scream at me about grillster (plz. plz scream at me about grillster) you can do so here or over at my tumblr, [parsnipit!](https://parsnipit.tumblr.com/) :D


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